To Many automobile drivers speeding.
Drivers today are exceeding the speed limits and displaying unsafe acts that is a threat to bikers.
I stopped riding my bike several years ago because of careless drivers.
Some drivers so close to you that their side mirrors brushed your shoulder, cutting in front of you and blowing their horns when they are next to you.
Then there are the hit and run drivers so what good is a helmet if your rear ended at 70 miles an hour?